145 research outputs found
Insights into the evolution of mammalian telomerase: Platypus TERT shares similarities with genes of birds and other reptiles and localizes on sex chromosomes
Background The TERT gene encodes the catalytic subunit of the telomerase complex and is responsible for maintaining telomere length. Vertebrate telomerase has been studied in eutherian mammals, fish, and the chicken, but less attention has been paid to other vertebrates. The platypus occupies an important evolutionary position, providing unique insight into the evolution of mammalian genes. We report the cloning of a platypus TERT (OanTERT) ortholog, and provide a comparison with genes of other vertebrates. Results The OanTERT encodes a protein with a high sequence similarity to marsupial TERT and avian TERT. Like the TERT of sauropsids and marsupials, as well as that of sharks and echinoderms, OanTERT contains extended variable linkers in the N-terminal region suggesting that they were present already in basal vertebrates and lost independently in rayfinned fish and eutherian mammals. Several alternatively spliced OanTERT variants structurally similar to avian TERT variants were identified. Telomerase activity is expressed in all platypus tissues like that of cold-blooded animals and murine rodents. OanTERT was localized on pseudoautosomal regions of sex chromosomes X3/Y2, expanding the homology between human chromosome 5 and platypus sex chromosomes. Synteny analysis suggests that TERT co-localized with sex-linked genes in the last common mammalian ancestor. Interestingly, female platypuses express higher levels of telomerase in heart and liver tissues than do males. Conclusions OanTERT shares many features with TERT of the reptilian outgroup, suggesting that OanTERT represents the ancestral mammalian TERT. Features specific to TERT of eutherian mammals have, therefore, evolved more recently after the divergence of monotremes.Radmila Hrdličková, Jiřà Nehyba, Shu Ly Lim, Frank Grützner, Henry R Bose J
Interobserver and intraobserver agreement of ligamentous injuries on conventional MRI after simple elbow dislocation
Indikationskriterien zur valgisierender Umstellungsosteotomie bei fehlgeschlagener hĂĽftgelenksnaher Frakturversorgung
Vergleich von Kurzzeit- und Langzeitergebnissen nach offener Bankart-Operation mit Knochenankern
Ist das Viper-2-System ein geeignetes Instrumentarium zur percutanen Versorgung von Wirbelfrakturen?
Ist das Viper-2-System ein geeignetes Instrumentarium zur percutanen Versorgung von Wirbelfrakturen?
Reality-augmented virtual fluoroscopy for computer-assisted diaphyseal long bone fracture osteosynthesis: A novel technique and feasibility study results
Vergleich von Kurzzeit- und Langzeitergebnissen nach offener Bankart-Operation mit Knochenankern
100 pagesThe City of Turner Parks System Master Plan (Master Plan or Plan) provides a ten-year vision for the City of Turner Parks System. The Master Plan articulates the community's vision to provide healthy and enjoyable recreational opportunities to city residents and visitors. The Park System Master Plan update and accompanying five-year Capital Improvement Program (CIP) provide a guide for the city to plan and develop the park system according to the community's needs
Effektivität unterschiedlicher präklinischer Infusionsregime beim traumatischen Blutungsschock - Eine Auswertung aus dem TraumaRegister DGU
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